﻿using System.Data;

namespace YiSha.Util;

public static class DataTableHelper
{
    public static DataTable ListToDataTable<T>(List<T> entitys)
    {
        //检查实体集合不能为空
        if (entitys == null || entitys.Count < 1)
        {
            throw new Exception("需转换的集合为空");
        }
        //取出第一个实体的所有Propertie
        Type entityType = entitys[0].GetType();
        PropertyInfo[] entityProperties = entityType.GetProperties();

        //生成DataTable的structure
        //生产代码中，应将生成的DataTable结构Cache起来，此处略
        DataTable dt = new DataTable();
        for (int i = 0; i < entityProperties.Length; i++)
        {
            dt.Columns.Add(entityProperties[i].Name);
        }
        //将所有entity添加到DataTable中
        foreach (object entity in entitys)
        {
            //检查所有的的实体都为同一类型
            if (entity.GetType() != entityType)
            {
                throw new Exception("要转换的集合元素类型不一致");
            }
            object[] entityValues = new object[entityProperties.Length];
            for (int i = 0; i < entityProperties.Length; i++)
            {
                entityValues[i] = entityProperties[i].GetValue(entity, null);
            }
            dt.Rows.Add(entityValues);
        }
        return dt;
    }
}